(UroToday.com) The 2022 GU ASCO Annual meeting included a prostate cancer session highlighting work from Dr. Amanda Hird and colleagues presenting their results of a population-based analysis assessing the prevalence and natural history of non-metastatic castrate resistant prostate cancer (nmCRPC). The natural history of nmCRPC prior to the introduction of novel anti-androgen agents in a real-world setting is largely unknown. Thus, the objective of this study was to determine the prevalence and natural history of nmCRPC in a large historical population-based cohort prior to the adoption of androgen receptor axis-targeting therapies (ARAT).
This was a retrospective population-based cohort study of men with nmCRPC in Ontario, Canada. Patients with a diagnosis of prostate cancer, castrate level of testosterone (< 1.7nmol/L) and a PSA > 2.0nmol/L with a subsequent rise > 25% from the nadir, and without diagnostic or treatment codes for metastasis were included. The annual prevalence of nmCRPC was calculated, and the crude time from nmCRPC to metastasis and death were presented as medians with interquartile range (IQR). Predictors of time from nmCRPC to prostate cancer death were compared using univariable and multivariable Fine and Gray subdistribution hazard models to account for the competing risk of non-prostate cancer death.
From January 2007 until March 2018, there were 2,045 patients identified with nmCRPC. The median age was 79 years (IQR: 72-84), and a total of 984 patients (48.1%) received upfront hormonal therapy, while 584 (25.8%) received initial radiotherapy (RT) and 478 (23.4%) underwent radical prostatectomy as their primary treatment. The median time from primary treatment to nmCRPC was 6 years (IQR: 3-10), and the median PSA at the time of meeting nmCRPC criteria was 3.0 ng/L. Patients were followed for a median of 31.1 months (IQR: 19.8-47.9). The overall annual prevalence of nmCRPC ranged from 1,519-1,913 patients, representing 7-12% of men with prostate cancer prescribed ADT each year. Crude median time from nmCRPC to all-cause death was 37.6 months (IQR: 22.1-55.4), and the median time from nmCRPC to metastasis and metastasis to all-cause death was 20.0 and 8.3 months, respectively:
On regression analysis, older age, higher PSA at the time of meeting nmCRPC criteria, and patients with grade group 4-5 disease predicted shorter time from nmCRPC to death.
Dr. Hird concluded her presentation assessing the prevalence and natural history of nmCRPC with the following take-home messages:
- This is the largest analysis of the prevalence and natural history of nmCRPC
- On average, 8% of men receiving ADT annually had nmCRPC and median overall time from nmCRPC to metastasis and metastasis to death was 20,0 and 8. 3 months, respectively
- Given that the study period was prior to the introduction of ARAT for nmCRPC and prior to the more widespread use of novel imaging modalities to detect metastasis, this study provides a historical reference for the approximate prevalence and expected disease trajectory for patients with nmCRPC
Presented by: Amanda E. Hird, MD, Division of Urology, Sunnybrook Health Sciences Center, University of Toronto, Toronto, ON, Canada
Co-Authors: Erind Dvorani, Refik Saskin, Sender Herschorn, Ronald Kodama, Girish S. Kulkarni, Robert Nam
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2022 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, Thursday Feb 17 – Saturday Feb 19, 2022